Thread trimmer for sewing machines



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C. H. T. HAGELSTEHN THREAD TRIMMER FOR SEWI-NG MACHINES Filed March' 15 1922 3 Sheets-Shem l 112 Q WEQQ H; T. HACEEQLSTEHN Taiwan) TRIMMER FOR SEWING MACHINES Filed March 15 192 5 Sheets-Sheet 3 Fig.3,

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C. H. T. HAGELSTEIN THREADERIMMER FOR SEWING MACHINES Filed March 15 2 3 Sheets-Sheet 5 CHRISTIAN 'll'. HAGELSEEIN, 0.1T BGSTON, MASSACHUSETTS, ASSIGNO'B; TO REECE BUTTON MJEfiE-IINE GOMIEJMNY, BOSTON, MASfiAGHUSET'IES, COREOIMLIION 01$ MAINE.

THREAD TLRIMMEIFJ F03; SEWING IvfiIAGl-IINES.

Application filed March 15, 192-2. Serial No. 543,987.

To all whom it may concern:

Be it known that l, CHRISTIAN H. T. HiienLsTniN, a citizen of theUnited i 'itates and resident of Boston, county of Suffolk, Satate of liltassachusetts, have invented an improvement in Thread Trimmers for Sewing Machines, of which the following de scription, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to threadtrimming devices for sewing machines of the twothread type, and it has for one of its objects to improve the thread-trimming devices illustrated in my Patent No. 1,395,274, dated Nov. 1, 1921.

The device illustrated in said patent is provided with a thread selector which operates during the formation of. the last stitch and while the shuttle is being inserted through a loop of needle thread to separate the shuttle thread and the end of the needle thread which leads to the work from the other end of the needle thread, and then to sever the separated ends close to the work, thereby leaving beneath the work a length of needle thread which formerly constituted the loop of needle thread and which is sui'licient to insure the correct formation of the first stitches when the stitching operation begins again.

My present invention aims to improve this thread trimming device by providing thread separator which operates before the thread selector to engage the side of the loop of needle thread which is not to be out and carry said side of thread to one side and entirely out of the way of the cutter so as to obviate any possibility that this side of the needle thread will be severed when the thread is out.

Another object of the invention is to provide further improvements in the manner.

of holding. and manipulating the thread so that the loop of thread will be held taut while it is being separated and while the cutter is acting thereon.

Other objects of the invention areto still further improve thread-cutting device'sof this type all as will be more fully hereinafter set forth.

ltn the drawings, Fig. 1 is a side View of a sewing machine such as illustrated in my above-mentioned Patent No. 1,3952% and to which my present inventions are applied.

Fig. 2 is a fragmentary perspective view showing the operation of the thread-cutting mechanismj i i i i Fig. 8 is a bottom plan view of the sewing machine illustrating the thread cutting vice in one position. i

Fig. 4 is a fragmentary bottom plan view illustrating the thread cutter in another position. i i i Fig. 5 is a vertical sectional view showing the position of the thread after the loop has been Spread andwhen the needlethread is about to be cut.

Figs. 6 and 7 are plan views of the threadcutting device showing the parts in differ ent position.

Fig. 8 is a bottom plan view of the throat plate;

Fig. 9 is a vertical sectional view.

The sewing machine'here'in illustrated is one designed for inserting reinforcing stitches 1, 2 at the ends of a buttonhole i'l which has been formed in a piece of work 1, or at the ends of pocket openings in a garment or at any other place where such reinforcing is necessary. 'A sewing machine of this type is frequently referred to in the trade as a tacker.

The stitch-forming mechanism by which the stitches 1 and 2 are formed con rif'es the usual eye-pointed needle 5 carried by a needle bar 6 which reciprocates vertically in the overhanging arm 7 of the sewing machine frame and operates through a throat plate 20, and a shuttle 8, whichmay be either a rotary or an oscillatory shuttle and which is situated beneath the work support 10 on which the work 1 is received. Both the needle bar and the shuttle derive their movement from a driving shaft 11 by any suitable or usual connections. The work 4 in which the stitches 1 and 2 are to be formed is held in a work clamp comprising two work clamping members 12 and 13. The upper clamping member 12 is pivoted at 14 to a stud 15 rising from the under clamping member 13 and is acted upon by a spring 16 which yieldingly holds the two clamping members in clamping engagement with the work. The work clamp is given a vibratort motion in two different directions, the motion in one direction producing the long stitches 1 extending transversely of the buttonhole and the motion "in the other direction pro-- ducing the shorter stitches 2 which cross the long stitches at right angles. These two movements of the work clamp are derived from a cam member 17 which has worm teeth 18 on its periphery that mesh with and are driven by a worm 19 on the shaft 11 all as shown in the above-mentioned patent. The connections between the cam 17 and the work clamp are or may be all as illustrated in the above-mentioned patent.

In sewing machines of this general type the needle 5 upon its penetrating thrust carries a loop of needle thread through the fabric and through the throat plate and as the needle rises the loop is taken by a suitable hook associated with the shuttle and is can ried around the shuttle thereby to concatenate the shuttle thread with the needle thread.

In the present drawings the shuttle thread is indicated at 21 and the loop of needle thread through. which the shuttle has passed is indicated at 22.

In the device illustrated in my above-mentioned Patent No. 1,395,274: a thread selector is employed which operates during the formation of the last stitch and while the shuttle is passing through the loop of needle thread to engage the side of the loop 22 of needle thread leading to the work and also the shuttle thread and carrying them to one side and into position to be severed by the thread cutter.

It sometimes happens, however, that during the rapid operation of the machine the thread selector does not operate accurately and one of the objects of my present invention is to provide an improved means which will assist the thread selector to engage only one side of the loop of needle thread thereby making it positive that the side of said loop which leads to the needle will not be acted on by the cutter.

My present improvement includes the thread selector illustrated in my above-mentioned patent and in addition thereto a loop separator which co-operates with the selector to insure that the sides of the loop are properly spread so that the cutter will function accurately; j

The thread selector is indicated at 23 and is constructed similarly to the thread selector in my abovesmentioned patent, it comprising a curved member pivotally mounted on a shaft. 24 carried by the frame and having at its end a notch 25 adapted to engage the threads as presently described. This threadselector is acted upon by a pulling spring 26 which normally tends to maintain it in the position shown in Fig. 6 with its end'against an adjustable stop 27. The shaft 24.01 which'the selector 23 is pivoted, 1s 1n turn ournalled in suitable hearings in the frame and has fast thereon an arm 28 provided with a projection 29 adapted to engage the thread selector. The shaft 24 has fast thereon an arm 31 having a cam portion 32 at its end which co-operates with a projection formed on the cam 17 for giving operative movement to the thread selector. This arm 31 is acted on by a pulling spring 34. which tends to hold it in the position shown in Fig. 3.

Associated with the thread selector is a loop spreader in the form of a finger 35 which is pivotally mounted on the frame as shown at 36 and is acted upon by a spring 37 tending to hold it in the position shown in Fig. 6. The spring-impelled movement of the loop spreader is limited by the en gagement of the tail 38 thereof with the stop 39.

The loop spreader is provided at its end with a beak i0 which is situated just back of the needle hole through the throat plat 20 as seen in Figs. 6 and 7 and during the formation of the last stitch when the loop 22 of needle thread is passing about the shut tle said loop will be spread suilicienlly by the shuttle so that the side of the loop lead ing to the needle which is on the further side of the shuttle will be deflected so as to be in the path of the beak 10 of the loop spreader. At this time the projection 33 on the cam 17 engages the end 512 of the arm 31 thus swinging the arm from the position shown in Fig. 3 to the position shown in Fig. 4, and this swinging movement of the arm 31 swings the arm 28 from the position shown in Fig. 6 to that shown in Fig. 7. During this movement of the arm 28 the projection 20 engages the thread selector and moves it backwardly into the position shown in Fig. 7 and during the final movement of the arm 28 it engages the loop spreader and also swings it backwardly to the position shown in Fig. 7.

These movements occur while the loop of needle thread for the last stitch is being carried around the shuttle by the shuttle hook and as said loop 22 of needle thread is drawn backwardly by the shuttle hook duu ing the operation of carrying the loop about the shuttle. the loop spreader 35 is moved forwardly into the position shown in Fig. 6 and during this forward movement the beak 40 thereof engages the side 42 of the loop 22 of the needle thread. this being the side of the loop which leads to the needle, and draws said side of the loop laterally and away from the opposite side of the loop and out of the path of the movement of the thread selector. After the loop spreader has operated as above described. the thread selector 23 moves forwardly into the position shown in Fig. 6 and during this movement the notch 25 thereof engages the other side 4-3 of the loop ill) lllll moss of needle thread which leads to the Work and also engages the shuttle thread 21 and carries them laterally in a different direction from the side of the loop of needle thread and into a position to be cut by the thread cutter.

The movements of the loop spreader and thread selector from the position shown in Fig. 6 to that shown in Fig. 7 are secured. by the projection 83 engaging the cam end 32 of the lever 31. and after the projection passes the point 78 of the cam then said projection will have engagement with the face 79 of the cam and as the member 17 turns said projection 33 will move down said side of the cam thus controlling the spring-impelled return movement of the thread selector and loop spreader from the position shown in Fig. 7 to that shown in Fig. 6.

This return movement of the parts occurs as the loop 22 is fed from the shuttle so that when the parts have returned to the position shown in Figs. 3 and 6 said loop 22 will be retained by the loop spreader 40 and the thread selector 23 as shown in Fig. 5.

The thread is cut by means of a reciprocating cutter 44 having a cutting edge 45. This cutter is provided with a shank 46 which slides in suitable bearings 47 carried by the frame.

The cutting portion of the knife operates in a notch or slot formed in the throat plate 20 and this is provided for by securing to the bottom of the throat plate a plate 48 which has an opening therein larger than that through the main portion of the throat plate. This opening is of the shape best seen in Fig. 8, it having the enlarged portion 49 and the lateral slot- 50 communicat iug; therewith.

The parts are so disposed that when the side 42 of the needle thread is drawn later-- ally by loop spreader 35 said side will be drawn into the slot 50 and will thus be protected by the slot. The other side- 43 of the loop is drawn by the thread selector 23 to the opposite end of the opening 4-9 and is thus brought into the line'of travel of the cutting edge 45 of the knife.

The knife 44 is given its reciprocating movement in one direction by the thread selector 23 and in the other direction by the arm 28. The thread cutter is shown as having a lateral projection 51 and the thread selector 23 is formed with a toe portion 52 adapted to engage said projection 51 when the thread selector is moved from the posi tion shown in Fig. 6 to that shown in Fig. 7, this engagement of the toe 52 with the projection 51 carrying the knife forwardly into the position shown in Fig. 7.

The cutting movement of the knife is derived from the arm 28 as it moves from the position shown in Fig. 7 to that shown in the thread selector has operated to en age the side 43 of the needle loop and carry it into position to be cut. Fiaid arm 2% is provided with an extension adapted to i.- the projection 51 when the arm from the position shown in. Fig. 7 to that shown in Fig. 6, such engagement giving the cutter its thread-cutting movement,

When the thread selector has its operative movement from the position shown in Fig. 7 to that shown in Fig. 6 the arm 28 moves with it because of the engagement be tween the thread selector and the projection 29.

The extension 53 of the arm 28, however, does not engage the projection 51 until about the time that the thread selector comes to rest. and after said thread selector has been positioned by the stop 27 the arm 28 continues its movement into the position shown in Fig. 6 thereby giving the knife its cutting movement, thereby to cut the side 43 of the loop of needle thread and also to cut the shuttle thread. During its cutting movement the other side 4.2 of the loop is withdrawn from the path of the knife by the loop spreader and is protected by being confined in the slot 50. There is, therefore, no possibility that the side 12 of the needle thread can be out or severed. This cutting of the needle thread takes place while the needle raised and the rising movement of the needle draws the loop 22 taut about the thread selector and the loop spreader so that the cutting operation will be accurately performed.

lVhile I have herein illustrated a selected embodiment of the invention I do not wish to be limited to the constructional features shown.

I claim:

1. In a sewing machine constructed to sew a short seam and then come to rest and having needle a shuttle, and means for operating them to cause a loop of needle thread to be carried about the shuttle, the combination with a loop spreader operative during the formation of the last stitch to engage the side f the loop of needle thread leading to the needle and draw it out. of a thread selector operative to engage the other side f said loop and carry it in another direction, and means to cut the latter side of the loop while said loop is retained by the thread selector and loop spreader.

2. In a sewing machine constructed to sew a short seam and then come to rest and having a needle, a shuttle, and means for op erating them to cause a loop of needle thread to be carried about the shuttle, the combination with a loop spreader operative during the formation of the last stitch to engage the side of the loop of needle thread leading to the needle and draw it out, of a Fig. 6. this movement occurring just after Mil thread. selector operative to engage the other side of said loop and carry it in another direction, means for controlling the movements of the selector and spreader, and means actuated thereby to cut the latter side of the loop.

3. In a sewing machine constructed to sew a Short seam and then come to rest and having a needle, a shuttle, and means for operating them to cause a loop of needle thread to be carried about the shuttle, the combination with a throat plate through which the needle operates and which is provided with a thread-receiving slot, of a loop spreader operative during the forma tion of'the last stitch to engage the side of the loop of needle thread leading to the needle and carry it into the slot, a thread selector to engage the opposite side of said loopand carry it in another direction, and means to sever the latter side of the loop.

4c. In a sewing machine constructed to sew a short seam and then come to rest and having a needle, a shuttle, and means for operating them to cause a loop of needle thread tobe carried about the shuttle, the combin-ation with a throat plate through which the needle operates and which is provided with a thread-receiving slot, of a loop spreader operative during the formation of the last stitch to engage the side of the loop of needle thread leading to the needle and carry it into the slot, a thread selector to engage the opposite side of said loop and carry it in another direction, means for controlling the movements of the selector and spreader, and means actuated thereby to cut the latter side of the loop.

5.1n a sewing machine constructed to sew a short seam and then come to rest and having a needle, a shuttle, and means for operating them to cause a loop of needle thread to ice carried about the shuttle, the

combination with a throat plate having an.

opening in which the needle operates and also having a knife-receiving slot intersecting said opening, of means operative during the formation of the last stitch to spread the loop of needle thread and carry the side thereof leading to the work into said slot. and a knife operating in said slot for severing said side of the thread.

6. In a sewing machine constructed to sew a short seam and then come to rest and having a needle, a shuttle, and means for operating them to cause a loop of needle thread to be carried about the shuttle, the combination with a throat plate having an opening in which the needle operates and also having a knife-receiving slot intersectim said opening, of means operative during the for mation of the last stitch to spread the loop of needle thread and carry the side thereof leading to the work laterally into said slot, a knife operating in said slot for severing said side of the thread, and means to protect the other side of said loop from being cut by the knife.

7. In a sewing machine constructed to sew a short seam and then come to rest and having a needle, a shuttle, and means for operating them to cause a loop of needle thread to be carried about the shuttle, the combination with a throat plate having an opening in which the needle operates and also having a knife-receiving slot inter secting said opening, a l-ooper spreader operating during the formation of the last stitch to engage the side of the loop of needle thread leading to the needle and draw it out, a thread selector operative to engage the other side of said loop and carry it in another direction, a knife operating in said slot for severing the latter side 01 the loop while said loop is retained by the thread selector and loop spreader.

8. In a sewing machine constructed to sew a short seam and then to come to rest and having a needle, a shuttle, and means for operating them to cause a loop of needle thread to be carried about the shuttle. the combination with a throat plate having an opening in which the needle operates and also having a lmife-reeeiving slot intersect ing said opening, a loop spreader operating during the formation of the last stitch to engage the side of the loop of needle thread leading to the needle and draw it out, a thread selector operative to engage the other side of said loop and carry it in another di rection, means for controlling the move-- ments of the selector and spreader, and a knife operating in said slot and actuated by said lastnamed means for severing one side of the loop.

In testimony whereof, I have signed my name to this specification.

CHRISTIAN H. T. HAGELSTEIN. 

